<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        #canvas{
            border: 1px solid;
        }
    </style>
</head>
<body>
    <canvas width="400" height="400" id="canvas">
        请升级你的服务器
    </canvas>
    <script>
        var canvasBox = document.querySelector('#canvas')
        var context = canvasBox.getContext('2d');
        console.log('context',context)
        context.fillStyle='#f99';
        context.fillRect(200,200,100,100);
        
        
    </script>
</body>
</html>